The Rhodamine Isothiocyanate Analogue as a Quorum Sensing Inhibitor Has the Potential to Control Microbially-Induced Biofouling

Quorum sensing inhibitors (QSIs) have been proven to be an innovative approach to interfering with biofilm formation, since this process is regulated by QS signals. However, most studies have focused on single-species biofilm formation, whereas studies of the effects of signal interference on the development of multispecies biofilm, especially in the natural environment, are still lacking. Here we develop and evaluate the anti-biofilm capability of a new QSI (rhodamine isothiocyanate analogue, RIA) in natural seawater. During the experiment, biofilm characteristics, microbial communities/functions and network interactions were monitored at 36, 80, and 180 h, respectively. The results showed that the biomass and 3D structure of the biofilm were significantly different in the presence of the QSI. The expression of genes involved in extracellular polysaccharide synthesis was also downregulated in the QSI-treated group. Dramatic differences in microbial composition, β-diversity and functions between the RIA-treated group and the control group were also observed, especially in the early stage of biofilm development. Furthermore, co-occurrence model analysis showed that RIA reduced the complexity of the microbial network. This study demonstrates that rhodamine isothiocyanate analogue is an efficient QS inhibitor and has potential applications in controlling biofouling caused by multispecies biofilm, especially in the early stage of biofouling formation.

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Effects of CO2laser irradiation on matrix-rich biofilm development formation–an in vitro study

PeerJ ◽

10.7717/peerj.2458 ◽

2016 ◽

Vol 4 ◽

pp. e2458 ◽

Cited By ~ 6

Author(s):

Bruna Raquel Zancopé ◽

Vanessa B. Dainezi ◽

Marinês Nobre-dos-Santos ◽

Sillas Duarte ◽

Vanessa Pardi ◽

...

Keyword(s):

Contact Angle ◽

Biofilm Formation ◽

Dental Enamel ◽

In Vitro Study ◽

Dry Weight ◽

Vitro Study ◽

Enamel Surface ◽

Control Group ◽

Biofilm Development

BackgroundA carbon dioxide (CO2) laser has been used to morphologically and chemically modify the dental enamel surface as well as to make it more resistant to demineralization. Despite a variety of experiments demonstrating the inhibitory effect of a CO2laser in reduce enamel demineralization, little is known about the effect of surface irradiated on bacterial growth. Thus, this in vitro study was preformed to evaluate the biofilm formation on enamel previously irradiated with a CO2laser (λ = 10.6 µM).MethodsFor this in vitro study, 96 specimens of bovine enamel were employed, which were divided into two groups (n = 48): 1) Control-non-irradiated surface and 2) Irradiated enamel surface. Biofilms were grown on the enamel specimens by one, three and five days under intermittent cariogenic condition in the irradiated and non-irradiated surface. In each assessment time, the biofilm were evaluated by dry weigh, counting the number of viable colonies and, in fifth day, were evaluated by polysaccharides analysis, quantitative real time Polymerase Chain Reaction (PCR) as well as by contact angle. In addition, the morphology of biofilms was characterized by fluorescence microscopy and field emission scanning electron microscopy (FESEM). Initially, the assumptions of equal variances and normal distribution of errors were conferred and the results are analyzed statistically by t-test and Mann Whitney test.ResultsThe mean of log CFU/mL obtained for the one-day biofilm evaluation showed that there is statistical difference between the experimental groups. When biofilms were exposed to the CO2laser, CFU/mL and CFU/dry weight in three day was reduced significantly compared with control group. The difference in the genes expression (Glucosyltransferases (gtfB) and Glucan-binding protein (gbpB)) and polysaccharides was not statically significant. Contact angle was increased relative to control when the surface was irradiated with the CO2laser. Similar morphology was also visible with both treatments; however, the irradiated group revealed evidence of melting and fusion in the specimens.ConclusionIn conclusion, CO2laser irradiation modifies the energy surface and disrupts the initial biofilm formation.

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Quorum Sensing Influences Burkholderia thailandensis Biofilm Development and Matrix Production

Journal of Bacteriology ◽

10.1128/jb.00047-16 ◽

2016 ◽

Vol 198 (19) ◽

pp. 2643-2650 ◽

Cited By ~ 23

Author(s):

Boo Shan Tseng ◽

Charlotte D. Majerczyk ◽

Daniel Passos da Silva ◽

Josephine R. Chandler ◽

E. Peter Greenberg ◽

...

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Bacterial Species ◽

Matrix Material ◽

Close Relative ◽

Wild Type ◽

Flow Conditions ◽

Burkholderia Thailandensis ◽

Content Type ◽

Biofilm Development

ABSTRACTMembers of the genusBurkholderiaare known to be adept at biofilm formation, which presumably assists in the survival of these organisms in the environment and the host. Biofilm formation has been linked to quorum sensing (QS) in several bacterial species. In this study, we characterizedBurkholderia thailandensisbiofilm development under flow conditions and sought to determine whether QS contributes to this process.B. thailandensisbiofilm formation exhibited an unusual pattern: the cells formed small aggregates and then proceeded to produce mature biofilms characterized by “dome” structures filled with biofilm matrix material. We showed that this process was dependent on QS.B. thailandensishas three acyl-homoserine lactone (AHL) QS systems (QS-1, QS-2, and QS-3). An AHL-negative strain produced biofilms consisting of cell aggregates but lacking the matrix-filled dome structures. This phenotype was rescued via exogenous addition of the three AHL signals. Of the threeB. thailandensisQS systems, we show that QS-1 is required for proper biofilm development, since abtaR1mutant, which is defective in QS-1 regulation, forms biofilms without these dome structures. Furthermore, our data show that the wild-type biofilm biomass, as well as the material inside the domes, stains with a fucose-binding lectin. ThebtaR1mutant biofilms, however, are negative for fucose staining. This suggests that the QS-1 system regulates the production of a fucose-containing exopolysaccharide in wild-type biofilms. Finally, we present data showing that QS ability during biofilm development produces a biofilm that is resistant to dispersion under stress conditions.IMPORTANCEThe saprophyteBurkholderia thailandensisis a close relative of the pathogenic bacteriumBurkholderia pseudomallei, the causative agent of melioidosis, which is contracted from its environmental reservoir. Since most bacteria in the environment reside in biofilms,B. thailandensisis an ideal model organism for investigating questions inBurkholderiaphysiology. In this study, we characterizedB. thailandensisbiofilm development and sought to determine if quorum sensing (QS) contributes to this process. Our work shows thatB. thailandensisproduces biofilms with unusual dome structures under flow conditions. Our findings suggest that these dome structures are filled with a QS-regulated, fucose-containing exopolysaccharide that may be involved in the resilience ofB. thailandensisbiofilms against changes in the nutritional environment.

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Quorum-Sensing Genes in Pseudomonas aeruginosa Biofilms: Their Role and Expression Patterns

Applied and Environmental Microbiology ◽

10.1128/aem.67.4.1865-1873.2001 ◽

2001 ◽

Vol 67 (4) ◽

pp. 1865-1873 ◽

Cited By ~ 341

Author(s):

Teresa R. De Kievit ◽

Richard Gillis ◽

Steve Marx ◽

Chris Brown ◽

Barbara H. Iglewski

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Biofilm Formation ◽

Fluorescent Protein ◽

Expression Patterns ◽

Homoserine Lactone ◽

Lower Percentage ◽

Spatial Studies ◽

Green Fluorescent ◽

Biofilm Development

ABSTRACT Acylated homoserine lactone molecules are used by a number of gram-negative bacteria to regulate cell density-dependent gene expression by a mechanism known as quorum sensing (QS). InPseudomonas aeruginosa, QS or cell-to-cell signaling controls expression of a number of virulence factors, as well as biofilm differentiation. In this study, we investigated the role played by the las and rhl QS systems during the early stages of static biofilm formation when cells are adhering to a surface and forming microcolonies. These studies revealed a marked difference in biofilm formation between the PAO1 parent and the QS mutants when glucose, but not citrate, was used as the sole carbon source. To further elucidate the contribution of lasI andrhlI to biofilm maturation, we utilized fusions to unstable green fluorescent protein in concert with confocal microscopy to perform real-time temporal and spatial studies of these genes in a flowing environment. During the course of 8-day biofilm development,lasI expression was found to progressively decrease over time. Conversely, rhlI expression remained steady throughout biofilm development but occurred in a lower percentage of cells. Spatial analysis revealed that lasI andrhlI were maximally expressed in cells located at the substratum and that expression decreased with increasing biofilm height. Because QS was shown previously to be involved in biofilm differentiation, these findings have important implications for the design of biofilm prevention and eradication strategies.

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Plantain Herb Extracts significantly attenuate the quorum sensing-controlled virulence factors and inhibit biofilm formation in Pseudomonas aeruginosa PAO1

E3S Web of Conferences ◽

10.1051/e3sconf/20197801004 ◽

2019 ◽

Vol 78 ◽

pp. 01004

Author(s):

Shan Li ◽

Jiangning Yao ◽

Haoming Li

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Virulence Factors ◽

Biofilm Formation ◽

Opportunistic Pathogen ◽

Significant Inhibition ◽

Control Group ◽

Produce Cell ◽

Group B ◽

Herb Extracts

Pseudomonas aeruginosa is a Gram-negative organism that can survive under harsh conditions, and it is also an opportunistic pathogen that can produce cell-associated extracellular virulence factors. Several of these virulence factors have been demonstrated to be regulated by quorum sensing (QS). Plantain Herb has been used as antibacterial agents for many centuries in China. In this study, we analyzed Plantain Herb Extracts (PHE) at the concentration of 16 μg/mL (Group A, MIC), 8 μg/mL (Group B, 1/2 MIC) and 4 μg/mL (Group C, 1/4 MIC) for inhibition of the virulence factors production and biofilm formation in P. aeruginosa PAO1. The virulence factors included pyocyanin, rhamnolipids, protease and alginate. PHE showed significant inhibition of virulence factors as compared to the control group without interfering its growth. Thus, PHE might be a potent QS inhibitor and anti-biofilm agent in the treatment of Pseudomonas aeruginosa infections.

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Trp-Containing Antibacterial Peptides Impair Quorum Sensing and Biofilm Development in Multidrug-Resistant Pseudomonas aeruginosa and Exhibit Synergistic Effects With Antibiotics

Frontiers in Microbiology ◽

10.3389/fmicb.2021.611009 ◽

2021 ◽

Vol 12 ◽

Author(s):

Dejing Shang ◽

Xue Han ◽

Wanying Du ◽

Zhiru Kou ◽

Fengquan Jiang

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibacterial Activity ◽

Quorum Sensing ◽

Virulence Factors ◽

Biofilm Formation ◽

Efflux Pump ◽

Synergistic Effects ◽

Multidrug Resistant ◽

Biofilm Development ◽

Antibiotic Efflux

Pseudomonas aeruginosa uses quorum sensing (QS) to control virulence, biofilm formation and antibiotic efflux pump expression. The development of effective small molecules targeting the QS system and biofilm formation represents a novel attractive strategy. In this present study, the effects of a series of Trp-containing peptides on the QS-regulated virulence and biofilm development of multidrug-resistant P. aeruginosa, as well as their synergistic antibacterial activity with three classes of traditional chemical antibiotics were investigated. The results showed that Trp-containing peptides at low concentrations reduced the production of QS-regulated virulence factors by downregulating the gene expression of both the las and rhl systems in the strain MRPA0108. Biofilm formation was inhibited in a concentration-dependent manner, which was associated with extracellular polysaccharide production inhibition by downregulating pelA, algD, and pslA transcription. These changes correlated with alterations in the extracellular production of pseudomonal virulence factors and swarming motility. In addition, the combination of Trp-containing peptides at low concentration with the antibiotics ceftazidime and piperacillin provided synergistic effects. Notably, L11W and L12W showed the highest synergy with ceftazidime and piperacillin. A mechanistic study demonstrated that the Trp-containing peptides, especially L12W, significantly decreased β-lactamase activity and expression of efflux pump genes OprM, MexX, and MexA, resulting in a reduction in antibiotic efflux from MRPA0108 cells and thus increasing the antibacterial activity of these antibiotics against MRPA0108.

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AbaM Regulates Quorum Sensing, Biofilm Formation and Virulence in Acinetobacter baumannii

Journal of Bacteriology ◽

10.1128/jb.00635-20 ◽

2021 ◽

Author(s):

Mario López-Martín ◽

Jean-Frédéric Dubern ◽

Morgan R. Alexander ◽

Paul Williams

Keyword(s):

Quorum Sensing ◽

Acinetobacter Baumannii ◽

Biofilm Formation ◽

Plant Pathogens ◽

Galleria Mellonella ◽

Homoserine Lactone ◽

Infection Model ◽

Wild Type ◽

Surface Motility ◽

Biofilm Development

Acinetobacter baumannii possesses a single divergent luxR/luxI-type quorum sensing (QS) locus named abaR/abaI. This locus also contains a third gene located between abaR and abaI which we term abaM that codes for an uncharacterized member of the RsaM protein family known to regulate N-acylhomoserine lactone (AHL) dependent QS in other β- and γ-proteobacteria. Here we show that disruption of abaM via a T26 insertion in A. baumannii strain AB5075 resulted in increased production of N-(3-hydroxydodecanoyl)-L-homoserine lactone (OHC12) and enhanced surface motility and biofilm formation. In contrast to the wild type and abaI::T26 mutant, the virulence of the abaM::T26 mutant was completely attenuated in a Galleria mellonella infection model. Transcriptomic analysis of the abaM::T26 mutant revealed that AbaM differentially regulates at least 76 genes including the csu pilus operon and the acinetin 505 lipopeptide biosynthetic operon, that are involved in surface adherence, biofilm formation and virulence. A comparison of the wild type, abaM::T26 and abaI::T26 transcriptomes, indicates that AbaM regulates ∼21% of the QS regulon including the csu operon. Moreover, the QS genes (abaI/abaR) were among the most upregulated in the abaM::T26 mutant. A. baumannii lux-based abaM reporter gene fusions revealed that abaM expression is positively regulated by QS but negatively auto-regulated. Overall, the data presented in this work demonstrates that AbaM plays a central role in regulating A. baumannii QS, virulence, surface motility and biofilm formation. Importance Acinetobacter baumanni is a multi-antibiotic resistant pathogen of global healthcare importance. Understanding Acinetobacter virulence gene regulation could aid the development of novel anti-infective strategies. In A. baumannii, the abaR and abaI genes that code for the receptor and synthase components of an N-acylhomoserine (AHL) lactone-dependent quorum sensing system (QS) are separated by abaM. Here we show that although mutation of abaM increased AHL production, surface motility and biofilm development, it resulted in the attenuation of virulence. AbaM was found to control both QS-dependent and QS-independent genes. The significance of this work lies in the identification of AbaM, an RsaM ortholog known to control virulence in plant pathogens, as a modulator of virulence in a human pathogen.

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Influence of fluconazole administration on gut microbiome, intestinal barrier and immune response in mice

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02552-20 ◽

2021 ◽

Author(s):

Xing Heng ◽

Yuanhe Jiang ◽

Weihua Chu

Keyword(s):

Immune System ◽

Gut Microbiota ◽

Relative Abundance ◽

Gut Microbiome ◽

Bacterial Flora ◽

Intestinal Barrier ◽

Treated Group ◽

Control Group ◽

Microbial Composition ◽

Control Serum

Antibiotics which can treat or prevent infectious diseases play an important role in medical therapy. However, the use of antibiotics has potential negative effects on the health of the host. For example, antibiotics use may affect the host's immune system by altering the gut microbiota. Therefore, the aim of the study was to investigate the influence of antifungal (fluconazole) treatment on gut microbiota and immune system of mice. Results showed that gut microbial composition of mice receiving fluconazole treatment was significantly changed after the trial. Fluconazole did not affect the relative abundance of bacteria but significantly reduced the diversity of bacterial flora. In the Bacteriome, Firmicutes and Proteobacteria significantly increased, while Bacteroidetes, Deferribacteres, Patescibacteria, and Tenericutes showed a remarkable reduction in fluconazole treated group in comparison with the control group. In the mycobiome, the relative abundance of Ascomycota was significantly decreased and Mucoromycota was significantly increased in the intestine of mice treated with fluconazole compared to the control group. RT-qPCR results showed that the relative gene expression of ZO-1, occludin, MyD88, IL-1β, and IL-6 was decreased in fluconazole-treated group compared to the control. Serum levels of IL-2, LZM and IgM were significantly increased, while IgG level had considerably down-regulated in the fluconazole-treated compared to the control. These results suggest that the administration of fluconazole can influence the gut microbiota and that a healthy gut microbiome is important for the regulation of the host immune responses.

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Mat fimbriae promote biofilm formation by meningitis-associated Escherichia coli

Microbiology ◽

10.1099/mic.0.039610-0 ◽

2010 ◽

Vol 156 (8) ◽

pp. 2408-2417 ◽

Cited By ~ 18

Author(s):

Timo A. Lehti ◽

Philippe Bauchart ◽

Johanna Heikkinen ◽

Jörg Hacker ◽

Timo K. Korhonen ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Early Stage ◽

Surface Expression ◽

Growth Media ◽

Biofilm Growth ◽

Abiotic Surfaces ◽

K 12 ◽

Biofilm Development

The mat (or ecp) fimbrial operon is ubiquitous and conserved in Escherichia coli, but its functions remain poorly described. In routine growth media newborn meningitis isolates of E. coli express the meningitis-associated and temperature-regulated (Mat) fimbria, also termed E. coli common pilus (ECP), at 20 °C, and here we show that the six-gene (matABCDEF)-encoded Mat fimbria is needed for temperature-dependent biofilm formation on abiotic surfaces. The matBCDEF deletion mutant of meningitis E. coli IHE 3034 was defective in an early stage of biofilm development and consequently unable to establish a detectable biofilm, contrasting with IHE 3034 derivatives deleted for flagella, type 1 fimbriae or S-fimbriae, which retained the wild-type biofilm phenotype. Furthermore, induced production of Mat fimbriae from expression plasmids enabled biofilm-deficient E. coli K-12 cells to form biofilm at 20 °C. No biofilm was detected with IHE 3034 or MG1655 strains grown at 37 °C. The surface expression of Mat fimbriae and the frequency of Mat-positive cells in the IHE 3034 population from 20 °C were high and remained unaltered during the transition from planktonic to biofilm growth and within the matured biofilm community. Considering the prevalence of the highly conserved mat locus in E. coli genomes, we hypothesize that Mat fimbria-mediated biofilm formation is an ancestral characteristic of E. coli.

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Characterization of detachment mode of biofilm developed in an attached-growth reactor

Water Science & Technology ◽

10.2166/wst.1994.0544 ◽

1994 ◽

Vol 30 (11) ◽

pp. 35-45 ◽

Cited By ~ 23

Author(s):

Akiyoshi Ohashi ◽

Hideki Harada

Keyword(s):

Shear Stress ◽

Biofilm Formation ◽

Early Stage ◽

Large Fraction ◽

Video Camera ◽

Cavity Formation ◽

Flat Surfaces ◽

Gas Vacuoles ◽

Biofilm Detachment ◽

Biofilm Development

In this study the in situ behavior of biofilm development and detachment was continuously observed by a video camera. The model biofilms consisting of denitrifiers were formed on the flat surfaces of polyvinyl-chloride plates that were placed in a rectangular open-channel reactor. The effects of intrinsic biofilm properties on biofilm detachment, such as intrafilm gas-vacuoles formation, extracellular biopolymer (ECP) content, biofilm density and cavity formation at the biofilm/substratum interface were quantified using attached-biofilms onto flat substrata. The result indicated that there were three phenotypes of massive biofilm detachment (see Fig. 4) under the conditions of low shear stress of flow. The first type showed that a large fraction (approximately 1/4-1/3) of the biofilm was sloughed off as a whole layer from the substratum surface at a relatively early stage of biofilm formation. This type was primarily caused by the cavity formation and by the decrease of ECP content. Succeeding to the first type, the second type occurred as fragmentary detachments. The second phenomenon was attributable to the increase in biofilm buoyancy due to the gas-vacuoles formation within the biofilm. The third type took place as the combination of the first and the second types following the occurrence of the second type. In contrast, at a higher flow shear stress only the second type of detachment became prevalent throughout the progression of biofilm formation.

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Inhibition of Candida albicans Biofilm Formation by Farnesol, a Quorum-Sensing Molecule

Applied and Environmental Microbiology ◽

10.1128/aem.68.11.5459-5463.2002 ◽

2002 ◽

Vol 68 (11) ◽

pp. 5459-5463 ◽

Cited By ~ 441

Author(s):

Gordon Ramage ◽

Stephen P. Saville ◽

Brian L. Wickes ◽

José L. López-Ribot

Keyword(s):

Candida Albicans ◽

Quorum Sensing ◽

Biofilm Formation ◽

Northern Blot Analysis ◽

Adherent Cell ◽

Naturally Occurring ◽

Biofilm Development ◽

Further Development ◽

Quorum Sensing Molecule

ABSTRACT Farnesol is a quorum-sensing molecule that inhibits filamentation in Candida albicans. Both filamentation and quorum sensing are deemed to be important factors in C. albicans biofilm development. Here we examined the effect of farnesol on C. albicans biofilm formation. C. albicans adherent cell populations (after 0, 1, 2, and 4 h of adherence) and preformed biofilms (24 h) were treated with various concentrations of farnesol (0, 3, 30, and 300 μM) and incubated at 37°C for 24 h. The extent and characteristics of biofilm formation were then assessed microscopically and with a semiquantitative colorimetric technique based on the use of 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide. The results indicated that the effect of farnesol was dependent on the concentration of this compound and the initial adherence time, and preincubation with 300 μM farnesol completely inhibited biofilm formation. Supernatant media recovered from mature biofilms inhibited the ability of planktonic C. albicans to form filaments, indicating that a morphogenetic autoregulatory compound is produced in situ in biofilms. Northern blot analysis of RNA extracted from cells in biofilms indicated that the levels of expression of HWP1, encoding a hypha-specific wall protein, were decreased in farnesol-treated biofilms compared to the levels in controls. Our results indicate that farnesol acts as a naturally occurring quorum-sensing molecule which inhibits biofilm formation, and we discuss its potential for further development and use as a novel therapeutic agent.

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